The blue tooth is initially conceived by Ericsson. The five founding members of the Bluetooth SIG are Ericsson, IBM, Intel, Nokia and Toshiba. On December 1, 1999, the founding members announced that 3COM, Lucent, Microsoft, and Motorola had joined the founders to form the Promoter Group with the founding companies. To date, more than 1,200 companies have signed up. Bluetooth is a standard for a small, inexpensive radio chip that connects to computers, printers, mobile phones, etc.
Blue tooth is a wire replacement technology. It uses radio frequencies in the 2.45 GHz range to transmit information over short distances, typically 33 feet (10 meters) or less. By integrating a Bluetooth chip and receiver into products, wires that would normally carry the signal can be eliminated.
A Bluetooth chip is designed to replace wires by taking the information normally carried by the wire and transmitting it at a special frequency to a receiving Bluetooth chip, which then feeds the received information to the computer, phone, or whatever.
Bluetooth Definitions
o Piconet: Devices connected ad hoc, that is, without the need for predefinition and planning, as in a standard network. Two to eight devices can be networked on a piconet. It is a peer network, that is, once connected, each device has the same access to the others. However, one device is defined as the master and the others as slaves.
o Sparse network: several piconets can form a larger sparse network, and each piconet maintains its independence.
o Master unit: The master in a piconet whose clock and hopping sequence synchronizes the other devices.
o Slave unit: Devices in a piconet that are not the master.
o MAC address: Three-bit address that distinguishes each unit in a piconet.
o Parked Units: Piconet devices that are synchronized but do not have MAC addresses.
o Sniff and hold mode: power saving mode of a piconet device.
Overview of Bluetooth features
These are the characteristics of Bluetooth technology:
1. Separate the frequency band into hops. This spread spectrum is used to hop from one channel to another, adding a strong layer of security.
2. Up to eight devices can be networked on a piconet.
3. Signals can be transmitted through walls and briefcases, thus eliminating the need for line of sight.
4. There is no need to point the devices at each other as the signals are omnidirectional.
5. Synchronous and asynchronous applications are supported, making it easy to deploy to a variety of devices and for a variety of services, such as voice and Internet.
6. Governments around the world regulate it, so it is possible to use the same standard wherever one travels.
How could Bluetooth be used?
Well, it depends a lot on our imagination. But the ambition is high, indeed; Virtually all of the computing equipment typically found in a modern office (and home) that doesn’t use a synchronous communications protocol could be adapted for use with Bluetooth.
Check this list:
Telephones and pagers, Modems, LAN access devices, Headsets, Laptops,
Desktop and laptop computers, printers, fax machines, keyboards, joysticks, etc.
Virtually any digital device can be part of the Bluetooth system. Bluetooth radio technology can also provide a universal bridge to existing data networks, a peripheral interface, and a mechanism to form small ad hoc groups of connected devices, far from fixed network infrastructures. The dynamic connectivity nature of Bluetooth makes it possible for this system to replace USB, and is an improvement on Plug-and-Play systems, where the operating system must be restarted for the installation to take effect.
Basic Bluetooth functions
Bluetooth technology is quite complex. This is not so surprising, considering the task you have to handle. It is primarily based on the IEEE 802.11 standard, briefly described to the right. Of the 2 network modes described, Bluetooth uses the ad-hoc mode. This means that each station must observe “netiqette” and give all other units fair access to wireless media.
The IEEE 802.11 communications standard defines the protocol for two types of networks; Ad-hoc and client/server.
How does Blue Tooth work?
Bluetooth uses frequency hopping at time intervals. Bluetooth has been designed to work in noisy RF environments and uses fast recognition and a frequency hopping scheme to make the communications link communication robust. Bluetooth radio modules avoid interference from other signals by hopping to a new frequency after transmitting or receiving a packet.
Compared to other systems operating in the same frequency band, Bluetooth radio generally hops faster and uses shorter packets. This is because short packets and fast hops limit the impact of microwave ovens and other sources of disturbance. The use of Forward Error Correction (FEC) limits the impact of random noise on long distance links.
Establishing network connections
The query and paging procedures are used to establish new connections. The query procedure allows a unit to discover which units are in range and what their device addresses and clocks are. With the paging procedure, a real connection can be established. Only the address of the Bluetooth device is required to establish a connection. Knowing about the clock will speed up the setup procedure. A unit that establishes a connection will carry out a search procedure and automatically become the master of the connection.
For the paging process, various paging schemes can be applied. There is a mandatory paging scheme that must be supported by every Bluetooth device. This mandatory scheme is used when the units meet for the first time, and in case the search process directly follows the consultation process. Two units, once connected using a mandatory search/scan scheme, can agree on an optional search/scan scheme.
What kind of traffic can Bluetooth handle?
Bluetooth is specifically designed to provide low-cost, robust, efficient, and high-capacity ad hoc voice and data networks with the following characteristics:
1. 1Mb/sec the transmission/reception speed takes advantage of the maximum available bandwidth of the channel.
2. Fast frequency hopping prevents interference.
3. Adaptive output power minimizes interference.
4. Short data packets maximize capacity during interference.
5. Fast recognition allows low coding overhead for links.
6. CVSD (continuously variable slope delta modulation) speech coding allows operation at high bit error rates.
7. Flexible package types support a wide range of applications.
8. The relaxed link budget supports low-cost single-chip integration.
9. Transmit/receive interface adapted to minimize power consumption
What about Bluetooth security?
Security can mean two things in this context:
o A) We want to be sure that the transmitted data reaches the recipient in perfect condition.
or B) We also want to feel that this data has not been spied on by people for whom it is not intended.
Both problems are (of course!) addressed by Bluetooth.
secure data transmission
Are transmissions safe in a business and home environment? Yes, they are supposed to be pretty reliable. Bluetooth has built in enough encryption and authentication and is therefore very secure in any environment. In addition to this, a frequency hopping scheme with 1600 hops/sec. is employed. This is much faster than any other competing system. This, together with an automatic output power adoption to reduce the range exactly to the requirement, makes the system extremely difficult to eavesdrop on.
